Means for decreasing leakage in turbines.



M 841,253. PATBNTED JAN. 15, 1507.

0. JUNGGREN.

MEANS POR DECREASING LEAKAGE IN TURBINES.

APPLIOATION FILED APR. 29; '1903.

F g. l lo -l2 E I4 mrmnng E ngwrwr.

Inventor:

muy.

l"UNIT-RD STATES- rA'rnNfr OFFICE.-

. OSCAR JUNCCREN, or'jsC'HENRCrAnY, ,NEW YORK, AssrGNoR To .GENERALELECTRIC COMPANY.- A CORPORATION or NEWIVY'ORK.

.ectady,

MEANS FOB DEQREASING LAKAG 'iN Tu-HsiNEs.

' pplieationled *April 29,

To au whom it may concer-1L: l

Be it known that I, OSCAR JUNGGREN,'a citizen of the United States,residing .at Schenin the county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Means for Decreasin'gthe'Leakage in Elastic-Fluid Turbines',v of

. which the following is a specification.

' In elasticeiiuid turbines itis customary to rovide a cover forv theouter ends of the wheel-buckets in order to'coniine the'motive4 fluid tothe passages between the buckets.v Situated between the wheel-bucketsare sta` ceive the motive buckets and discharge it at the proper angle4against .a second. set of wheel-buckets. Mani-l festly1 there must be yaclearance more or less A great between the relatively moving buckets,and through'this clearance considerable :steam or" other motive. iiuidleaks. The 'amount of thisleakage is also governed by the difference in.pressure betwe'en the column'of steam actually performing work and thatin the surrounding-casing or shell. 'I'he greater the difference inpressure, other 'things bein equal, the `greater the leakage.

My inven ion has forits object to decrease the leakage at theclearances, and to accomplish this I provide a means whereby' a hi hresistance or op osition is offered to the/lea motive iuid. v,

The covers ordinarily employed on. thev wheel-buckets are very thin,varyingv in thickness from one-eighth to three-sixteenths -of an inch.Owing' to the thinnessofy the l cover, .the surface friction opposingthe escape ofstea'm is verysma i.

lescapeof motive In carrylng out my invention I provide thebucket-covers with 'thickened edges, prefer-l ably taking "the form ofcircumferential flan es formedfinte al therewith. 'I he eX -g ten edsurfaces'of tIie thickenededge of the cover and the su ort forthe'intermediates offer a consideray higher-resistance to the fluid thandoes the normal passagebetween the buckets. yThe opposition orresistanceto leakage isnot so'great, however,A as to prevent the waterofl conden sation, and expansion `from beingdischar ed under centrifugalforcel ,'.The' amount t at the ailge or flan es project beyond the covervaries` with the c aracter and 'size of thetur-`4 Letters Patent.lattenwlv Jan. 15,1907. A

.woefl serai No. 154.888.

` For a fuller consideration of what I believe. to be -novel and myinvention attention is called to the description and claims appendedthereto.

illustrate one embodiment of my invention, Figure 1 is a partial axialsection of aturbine. Fig. 2 is asectional View of a wheel, takenon theline 2 2 of Fi .'1. axial section of a part o a bucket-wheel.. Fig. 4Yshows the bucket-Cover and interme- 'diate support grooved to furtherprevent leakage,l and Fig, 5' is adevelopment of the .tionaryforintermediate buckets, which re- V sectional bucket-cover.

-iiuid from one set of wheel- 1 represents the turbine casing or shell,and secured thereto.' is an adjustable nozzle 2, `whchjrnaybe. of thevexpanding or non-ex- 'anding type, as is desired. f In the particuar'illustration it is intended to convert the ressure of the elasticfluid4 into .velocity and eliver itin the form of a jet to the buckets;

nozzle is secured in place vby bolts 3 and is adjustable toward'and awayfrom the wheel in a plane parallel to its axis.- casing or shell isprovided .with 4an opening through which projects the 'segmental`support for, the intermediate buckets'.l The' sup` portgisvprovided'with, aliange 4 of somewhat greaterv area than the oeningwhich is se 4cured tothe outsideof'tllfe lCasin by bolts 5.,Between` hef`bodies of the bo ts and the f flan'ge is av small space,so that the intermediates can lbe vadjusted in'an `axial plane for thepurpose of changingthe'clearances between them andthe wheel-buckets. Theinh' selves measured in an axial plane; The ortion 8 of the su portadjacent to the wheel ticket-cover'y is a so 'somewhat wider' than y hebuckets measured4 in an axial plane, so as to reduce the leakage andrevent the sharpenededges of thebuckets om rubbing. The wheel-buckets 9are each provided with a 'shank.`10, formed integral therewithat thevinner end, and these shanks are fitted into a circumferential grooveformed in projections on the periphery of the wheel 11.

tend from one side to the otherof the saidi In 'theaccompanyingvdrawings, which i 6o Fig. 3 is" an but my invention is not limitedthereto.- The 'Theside of the The buckets are retained-inplace by pins12', which eX'-A projection or raisedlportion formed Aon thewheel-periphery-` The pins` being somewhat.

shorter than .the distance. between -theproj ections can readily 4vbeslipped' into 'place and the ends peened over .afte'rw'.ard,v I-'Thesides; ofthe projection arejin close `rnoiirn'ity to thc cover 7 oftheintermediate lbu'ckets, so, as tol reduce the circumferential orcross leakage at this point. The buckets may be formed b y-.drop-forging or casting, v.as l desired,I and eacn bue cover 13,sometimes 'calle a` fitting and baffling strip,y which cover has twothickened edges formedintegra'l therewith, which in the presentillustration take the form of circumferential flanges,14.`Infcrosssection the cover has the shape of a channel-beam; Thelclearance, measuredinv an. axial plane, `between the thickened edges orflanges 14 of the bucket-cover and the stationary parts, such as thenozzlcand the portion 8 of the'intermediate support, is made as small asypossiyble consistent with good operation. Through this clearancethe`waterl due to ,expansion and condensation can bedischarged; but theresistance or opposition to the passage of elastic motive fluid at ythispoint 1s high. Thisl is owing to thelfactthat theflange presents anextended surface to" the stationary part, and the frictional'resistanceoffered -to the outward passage'of' steam at'this point is consideerably greater than theresistance oeredto the, passage ofsteamthrough'the'normal' or yworkingpassages between the buckets.

In other words, two paths are provided for the steam. or other elasticfluid, one of low resistance and thev other. of relatively high 'resisteance, and owing to the fact that the jet-is traveling at high velocitydue. tol the nozzle only a very small amount of steam'willv be`permitte'd'to escape vthrough the/circumferential clearance. The waterdue to eXpansion and condensation also' has a tendency to decrease theleakage'by wettingthe adjacent surfaces of the moving and stationaryparts.

As the' intermediate buckets usually extend,-

thedifference in pressure between thel fluid stream and fluid or steamwithinthe shell or casingv the greatery willhe the 'depthoffthe `flangebecauseth'e tendency for the' steam to escape. at this ,point iscorrespondingly increased.

Referring 4to Fig. 2, it will `be seen that'the shanky 10 on eachbucketis taperedyandengages with similar-Shanks on adjacent bucket isvrovided with a ets and that the lcover .13 of each bucket is alsoslightly tapered and engages 'with the lcover-sections of adjacentbuckets. 'In this manner thegsteam or other motive fluid is confined tothe working passages 15.-

Referring to Fig. 3,1 have shown a slight modification of the invention,wherein the wheel-buckets 9 are formedintegral With segmental supports16, which in turn are secured to the wheel by bolts or'other attach-.ing means. i uIn this figure the line of division betweenthesegmentalsupports is'shown in l dotted lines. The buckets are provided withtenons 17, formed integral therewith, which register with openingsformed in the cover 13,

sometimes calledv a fitting and baffling strip. The cover uis preferablymadein se'ctions and is provided with thickened edges or flanges 14, asbefore. The tenons are riveted over to secure the cover-sections inplace.

have the cover-sections embrace a number of the buckets, because itysimplifies vthe 'machine-work.

The-'intermediate vbuckets used with the different structures should beof a suitable form, capable of receiving the motivefluid from one row ofwheel-buckets and changing its direction-and discharging it against thesecond :row of wheel-buckets at the roper angle. The buckets may -inVaddition to, changing the direction of the stream also act to impart acertain amount of Velocity to the stream.

In Fig. 4 the Wheel-cover and support for the lintermediate bucketsareshown on a*vv .In a construction 'of this kind it is desirable tosomewhat-enlarged scale, and -bothv are grooved circumferentially at 18to further prevent or reduce theleakage atfthe clear.-

ance. Asl the elastic'mo'tivefluid. tends-to escape it lcreates whirlsoryeddies in the grooves.

Fig. -shows a sectional bucket-cover developed on a flat pla-ne. videdwith ffangesM at-,the edges, whichare Each section is' pros IIO madestiff enough to prevent them from rub- 4 bing onvthe stationar partsAwhen subjected to fluid-pressure.. T e sections. are perfo. lrated at 19to receive the bucket-"tenons, and the adjacent'` endsofr the sectionsare prof "vided with notches '20, Which when the ends" are united form aperforation similar to 19.

.The cover' or fitting or baffiing strip can withl advanta'gebemadeoutof" fchannelf stockand preferably of steel.

'vv-The baffling ofl the motivev fluid may take lace at ythesideflangesofv the fittingv and afiling stri or cover 13, asshown ingconnecf`tion with vt e'intermediate' bucket-su ports -1 d) strip urpose,*thestruc-` 8','or the edges ,O f the flanges on sai may be utilized'for theture being the A'same in eit er casej" The 'said strip can serve-as a'baffling means on vboth the side and ed e at the same time, as. shown inthe upper riglit-handcorner oflilig.- 1 s i The bafiier disclosed4herein possesses'important advantages `over prior arrangements 1n theWay of Ibetter bathing effects and in the Way Aof v eatly-decreased costof manufac- 5 r ture. It 1s also well adapted to meet the condition ofaccidental rubbing of the parts. Aside 'from functioning as a bafflerthe said, baffle-strip or cover serves to ,-secure `tldieL -outer endsofthe buckets and form a partf'of xo the passagefor the motive fluid. Bymaking the strips out of solid stock with flanges at right anglesthereto it is a simple and inexpensive matter to turn or finish the faceor faces to. the required dimensions. Moreover, such a constructionrenders it vpossible to utilize workmen of ordinary skill. ,v v j It hasbeen .proposed heretofore to use laminated baflling devices forthefree-ends of turbine-buckets, and in some instances the 2o edges of thesaid devices have been s layed. vThls construction was an objection-a leone for various reasons, chief among which was the difficultyexperienced in turning them to a true surface. The thinness of the stock2 5 and the fact'that the ystructure wasv laminated with the edgesseparated in aninclined lane made it necessary to tool it very slowly 1norder to prevent tearing or s ringing of the metal, andthereforerequiredP eat care 3o and skill'. With .the structure. ilustrated thisobjection is overcome, and the parts can be made'sufliciently robust forall practicalv PTPOSGS y In accordance with the provisions of the patentstatutes I have described the principle of operation of my invention,together W1th the apparatus which I now consider to re resent the bestembodiment thereof; but I esire to have it understood that theappa- 4oratus shown is only illustrative and that the v inventioncan be carriedout in other ways.

What I claim as'new, and desire to secure by Letters Patent ofthevUnited Statesis- 1. In an elastic-fiuidturbine, the combination of acasing, a means for discharging motive fluid, a wheel, segmentalsupports mounted on the Wheel having integrallyformed buckets, a coverfor the buckets composed of a single layer having a thin central 5oportion and circumferential flanges at the edges, intermediate buckets,and sup orts therefor which are situated in line Wit the flanges and inclose proximity thereto.

2. In an elastic-fluid turbine, thecombination 'of a casing, a nozzle,intermediate buckets, a support therefor, a Wheel having buckets, a rowof buckets between the nozzle and the intermediates, and a cover f rythe wheel-buckets having a thin central lfdrtion 6o and circumferentialflanges which` project -beyondthe central .portion. and revolve inAclose proximity tof the nozzle andthe intermediate support. v

3. In an elastic-fluid'turbine, the combi' flanges,` and means foradjusting the support.,

toward or away from the cover-flanges.

4. In an elastic-fluid turbine, the combi- I nation of a casing, anozzle mounted thereon and -adjustable in a plane parallelwith thewheel-axis, a bucket-wheel, covers for the buckets having vcircumferential Hanges formed integral therewith, intermediate buckets,a support therefor ysituated in line with the flanges, and means foradjusting the support toward or away from the cover-flanges.

v5. Inv an elastic-fluid turbine, the combination of la plurality ofwheel-buckets, aA

cover therefor, circumferential flanges -at Aeach side of the cover,intermediatebuckets, a 'support therefor, and a groove opening into theclearance-space between the wheel and intermediate buckets fordecreasing the leakage. i

6. In an elastic-fluid turbine, the combilnation of a wheel or supporthaving a plurality of grooved projections Iformed on the periphery, aplurality of buckets, 'each having a shank that enters thegroove, aretaining means for each .bucket which passthrough' a projection and theshank, covers for each row of buckets,-and a row of intermediate bucketslocated between each two rows of wheel-buckets.

7. A bucket element vforan elastic-fluid turbine comprising a wheel orsupport with a plurality of buckets attached thereto, and a jointedcover for the buckets comprising a single layer,each section of thecover having a portionv which forms a part ofthe working passage, andintegral 'side portions extending at right angles or substantially atright an-A gles thereto for decreasing the leakage.

,8. In an elastic-fluidvturbine, the combination of a casing, a meansfor discharging motive fluid, buckets which are acted upon by the Huidand are formed integral with their support, a number,v of tenons eachformed integral with a bucket, and a cover `for the buckets which isheld in place by the IOO IIO

tenons, and has integral'flangesf occu ying planes parallel orsubstantially paralle with the edges of thel buckets.

'9. In a turbine, the combination, with its drum and' casing, of anumberof turbine-v a blades and aI fitting and baffling strip of channelshape in cross-section, one portion of I which is attached to. the freeends of the blades and the other portion of which .extends at rightangles to the turbine-axis.-

10. In a turbine, thecombination, with its drum and cylindrical casing,of a number of turbine-.blades and a fitting and baffling' strip 6 y;nation ofa casing, a nozzle for'discharging made of a single thicknessof stock'of channel shape in cross-section, the middle portion ot1`Which extends longitudinally and is attached to the free ends of theblades, and the other 'iro blades and a fitting and baffling stri madeof la single thickness of stock of angu ar crosssec-tion, one portion ofwhich is perforated to receive the'blade ends and attachedto the freeends of the blades by riveting over the blade ends which project throughthe perforations, and the other portion of which extends aWay from theblades transversely of the turbine-axis.l Y,

12. In a turbine, the combination, With its drum and casing, of a numberof turbineblades and a fitting and bathing strip divided into 'segmentallengths and made of a single thickness of stock of channel shape incrosssection, the iniddle portion of each segment being perforated andthe ends notched to receive the blade ends, thesaid fitting and baffiingstrip being attached to the free ends of the blades by riveting over theblade ends which project through the perforations, and the otherportions of which extend transversely away from the blades transverselyof the turbine-axis.

13. In a turbine, the combination, With its drum and casing, ofy anumber' of radial turbine-blades, anda channel-shaped fitting andbaffling strip attached to the free ends of the blades and extending atright angles to the turbineaxis,as set forth. i

14. In a turbine, the combination, with its drum and casing, of a numberof radial turbine-blades, and a iitting and baiiing strip made of asingle thickness of stock and at* tached to the free ends ofthe blades briveting and extending transversely of t efturbine-axis, as set forth.

-In Witness whereof I have hereunto set my hand this 28th day of April,1903.

4 e OSCAR JUNGGREN.- Witnesses: y n

L ALEX. F.1MACD0NALD, HELEN ORFORD.

